• 제목/요약/키워드: SATELLITE IMAGE

검색결과 2,146건 처리시간 0.026초

Analysis of Supercritical Shear Coaxial Jet Using Density Gradient Magnitude (밀도구배강도를 이용한 초임계 전단동축 제트 분석)

  • Lee, Keonwoong;Kim, Dohun;Son, Min;Han, Choyoung;Koo, Jaye
    • Journal of the Korean Society of Propulsion Engineers
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    • 제17권6호
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    • pp.59-66
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    • 2013
  • Spray characteristics of single round jet with liquid nitrogen and coaxial spray with liquid nitrogen and gaseous argon were observed. Shadowgraph method was used for spray visualization, and density gradient magnitude image was used to analyse the result. In subcritical condition, irregularity of the jet surface was harder in the coaxial spray. In supercritical condition, diffusion of nitrogen injected from shear coaxial injector was faster than single jet. Jet diameter was induced by averaging images, in supercritical condition, difference of diameter of coaxial jet was rapidly decreased than that of single jet.

Construction of Three Dimensional Virtual City Information Using the Web 3D (Web 3D를 이용한 3차원 가상도시공간정보 구축)

  • 유환희;조정운;이학균
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • 제20권2호
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    • pp.119-126
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    • 2002
  • Recently, as advancing the technologies for Web 3D and Virtual Reality, the studies have been progressed actively to provide three dimensional information on the web. Especially, the various applications for providing urban information in 3D space have been developed using EAI(External Authoring Interface) that serves an interface between VRML(Virtual Reality Modeling Language), standard language for embodying virtual reality, and JAVA applet in HTML. In this study, as constructing 3D virtual city information using Digital Map, IKONOS satellite image, VRML and so on, we could provide users which need several information with building location and various urban living information. In addition, applying 3D skills such as texturing, panorama and navigation, users were enabled to perform various route searching and scenery analysis. Finally, to serve urban living information in real time, we designed to search information faster through interfacing database and to update data using ASP(Active Server Page) on web.

Spatial analysis of Shoreline change in Northwest coast of Taean Peninsula

  • Yun, MyungHyun;Choi, ChulUong
    • Korean Journal of Remote Sensing
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    • 제31권1호
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    • pp.29-38
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    • 2015
  • The coastline influenced naturally and artificially changes dynamically. While the long-term change is influenced by the rise in the surface of the sea and the changes in water level of the rivers, the short-term change is influenced by the tide, earthquake and storm. Also, man-made thoughtless development such as construction of embankment and reclaimed land not considering erosion and deformation of coast has been causes for breaking functions of coast and damages on natural environment. In order to manage coastal environment and resources effectively, In this study is intended to analyze and predict erosion in coastal environment and changes in sedimentation quantitatively by detecting changes in coastal line from data collection for satellite images and aerial LiDAR data. The coastal line in 2007 and 2012 was extracted by manufacturing Digital Surface Model (DSM) with Aviation LiDAR materials. For the coastal line in 2009 and 2010, Normalized Difference Vegetation Index (NDVI) method was used to extract the KOMPSAT-2 image selected after considering tide level and wave height. The change rate of the coastal line is varied in line with the forms of the observation target but most of topography shows a tendency of being eroded as time goes by. Compared to the relatively monotonous beach of Taean, the gravel and rock has very complex form. Therefore, there are more errors in extraction of coastlines and the combination of transect and shoreline, which affect overall changes. Thus, we think the correction of the anomalies caused by these properties is required in the future research.

Visualization of 3D Terrain Information on Smartphone using HTML5 WebGL (HTML5 WebGL을 이용한 스마트폰 3차원 지형정보 시각화)

  • Kim, Kwang-Seob;Lee, Ki-Won
    • Korean Journal of Remote Sensing
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    • 제28권2호
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    • pp.245-253
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    • 2012
  • The public and civilian demands regarding 3D geo-spatial information processing on mobile device including smartphone are increasing. But there are few actual implementations or application cases. This work is to present some results by a prototype implementation of 3D terrain information visualization function with satellite image and DEM using HTML5 WebGL, which is a web-based graphic library under the standardization process. This is a useful standard for cross-platform operation for 3D graphic rendering without other plug-in modules. As the results, in the different types of operating system or browser in a personal computer or a smartphone, it shows same rendering results, as long as they support HTML5 WebGL. As well;geo-metadata search and identification functions for data sets for 3D terrain visualization process are added in this implementation for the practical aspect.

Study on the extraction of ocean wind, wave and current using SAR (SAR를 이용한 해풍, 파랑, 해류 추출 기법 연구)

  • Kang, Moon-Kyung;Park, Yong-Wook;Lee, Moon-Jin;Lee, Hoon-Yol
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 한국항해항만학회 2006년도 추계학술대회 논문집(제1권)
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    • pp.187-194
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    • 2006
  • Recently satellite SAR techniques have become essential observation tools for various ocean phenomena such as wind, wave, and current. The CMOD4 and CMOD-IFR2 models are used to calculate the magnitude of wind at SAR resolution with no directional information. Combination of the wave-SAR spectrum analysis and the inter-look cross-spectra techniques provides amplitude and direction of the ocean wave over a square-km sized imagette, The Doppler shift measurement of SAR image yields surface speed of the ocean current along the rador looking direction, again at imagette resolution. In this paper we report the development of a SAR Ocean processor (SOP) incorporating all of these techniques. We have applied the SOP to several RADARSAT-1 images of the coast of Korean peninsula and compared the results with oceanographic data, which showed reliability of spaceborne SAR-based oceanographic research.

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Study on the Extraction of Ocean Wind, Wave and Current using SAR (SAR를 이용한 해풍, 파랑, 해류 추출 기법 연구)

  • Kang, Moon-Kyung;Park, Yong-Wook;Lee, Moon-Jin;Lee, Hoon-Yol
    • Journal of Navigation and Port Research
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    • 제31권1호
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    • pp.35-42
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    • 2007
  • Recently satellite SAR techniques have become essential observation tools for various ocean phenomena such as wind, wave, and current. The CMOD4 and CMOD-IFR2 models are used to calculate the magnitude of wind at SAR resolution with no directional information. Combination of the wave-SAR spectrum analysis and the inter-look cross-spectra techniques provides amplitude and direction of the ocean wave over a square-km sized imagette, The Doppler shift measurement of SAR image yields surface speed of the ocean current along the radar looking direction, again at imagette resolution. In this paper we report the development of a SAR Ocean processor(SOP) incorporating all of these techniques. We have applied the SOP to several RADARSAT-1 images of the coast of Korean peninsula and compared the results with oceanographic data, which showed reliability of spaceborne SAR-based oceanographic research.

Relationship between Abundances of Kaloula borealis and Meteorological Factors based on Habitat Features (서식지 특성에 따른 맹꽁이 개체수와 기상요인과의 관계 분석)

  • Rho, Paikho
    • Journal of the Korean Society of Environmental Restoration Technology
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    • 제19권3호
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    • pp.103-119
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    • 2016
  • This study aims to assess habitat feature on the large-scale spawning ground of the Boreal Digging Frog Kaloula borealis in Daemyung retarding basin of Daegu, and to analyze the relationships between species abundance and meteorological factors for each habitat. Fifty-seven(57) pitfalls were installed to collect species abundance of 4 survey regions, and high-resolution satellite image, soil sampling equipment, digital topographic map, and GPS were used to develop habitat features such as terrain, soil, vegetation, human disturbance. The analysis shows that the frog is most abundant in sloped region with densely herbaceous cover in southern part of the retarding basin. In the breeding season, lowland regions, where Phragmites communis and P. japonica dominant wetlands and temporary ponds distributed, are heavily concentrated by the species for spawning and foraging. Located in between legally protected Dalsung wetands and lowland regions of the retarding basin, riverine natural levee is ecologically important area as core habitat for Kaloula borealis, and high number of individuals were detected both breeding and non-breeding seasons. Temperate- and pressure-related meteorological elements are selected as statistically significant variables in species abundance of non-breeding season in lowland and highland regions. However, in sloped regions, only a few variables are statistically significant during non-breeding season. Moreover, breeding activities in sloped regions are statistically significant with minimum temperature, grass minimum temperature, dew point temperature, and vapor pressure. Significant meteorological factors with habitat features are effectively applied to establish species conservation strategy of the retarding basin and to construct for avoiding massive road-kills on neighboring roads of the study sites, particularly post-breeding movements from spawning to burrowing areas.

An Analysis of Environmental Policy Effect on Green Space Change using Logistic Regression Model : The Case of Ulsan Metropolitan City (로지스틱 회귀모형을 이용한 환경정책 효과 분석: 울산광역시 녹지변화 분석을 중심으로)

  • Lee, Sung-Joo;Ryu, Ji-Eun;Jeon, Seong-Woo
    • Journal of the Korean Society of Environmental Restoration Technology
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    • 제23권4호
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    • pp.13-30
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    • 2020
  • This study aims to analyze the qualitative and quantitative effects of environmental policies in terms of green space management using logistic regression model(LRM). Landsat satellite imageries in 1985, 1992, 2000, 2008, and 2015 are classified using a hybrid-classification method. Based on these classified maps, logistic regression model having a deforestation tendency of the past is built. Binary green space change map is used for the dependent variable and four explanatory variables are used: distance from green space, distance from settlements, elevation, and slope. The green space map of 2008 and 2015 is predicted using the constructed model. The conservation effect of Ulsan's environmental policies is quantified through the numerical comparison of green area between the predicted and real data. Time-series analysis of green space showed that restoration and destruction of green space are highly related to human activities rather than natural land transition. The effect of green space management policy was spatially-explicit and brought a significant increase in green space. Furthermore, as a result of quantitative analysis, Ulsan's environmental policy had effects of conserving and restoring 111.75㎢ and 175.45㎢ respectively for the periods of eight and fifteen years. Among four variables, slope was the most determinant factor that accounts for the destruction of green space in the city. This study presents logistic regression model as a way of evaluating the effect of environmental policies that have been practiced in the city. It has its significance in that it allows us a comprehensive understanding of the effect by considering every direct and indirect effect from other domains, such as air and water, on green space. We conclude discussing practicability of implementing environmental policy in terms of green space management with the focus on a non-statutory plan.

Technique of Serving 3D GSIS Data on the Internet (인터넷3D GSIS를 위한 3차원 데이터의 효율적 구축 및 생성방안)

  • Kang, In-Joon;Lee, Jun-Seok
    • Journal of Korean Society for Geospatial Information Science
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    • 제10권1호
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    • pp.19-26
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    • 2002
  • To provide 3D GSIS data on the internet, 3D data structures need to be researched and applied for spatial analysis for subsurface modeling. As for GSIS software R&D trend the following things have pointed out : 3-dimensional geo-processing technologies, internet-based application system development, distributed processing technologies for large volume of spatial information, real-time geo-data processing methodologies, Among them research scope within Internet-based application system or Web-based GSIS generally contains core parts of software development such as Internet application, large volume of spatial database handling, real-time spatial data processing, spatial data transfer and transformation, and volumetric display of processing results. This study shows the method of providing 3D GSIS on the internet using VRML model, which are made of DEM data, draped aerial photo, and VRML script programming. And it is also studied that offering 3D GSIS engine on the internet and precise texture mapping using satellite image and aerial photos.

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Spectral Signatures of Tombs and their Classification (묘지의 분광적 특성과 통계적 분류)

  • Eunmi Change;Kyeong Park;Minho Kim
    • Journal of the Korean Geographical Society
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    • 제39권2호
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    • pp.283-296
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    • 2004
  • More than 0.5 percent of land in Korea is used for cemetery and the rate is growing in spite of the increase in cremation these days. The systematic management of tombs may be possible through the ‘Feature Extraction’ method which is applied to the high-resolution satellite imagery. For this reason, this research focused on finding out the radiometric characteristics of tombs and the classification of them. An IKONOS image of northwest areas of Seoul with 8km x 10km dimension was analyzed. After sampling 24 tombs in the study area, the statistical radiometric characteristics of tombs are analyzed. And tombs were classified based on the criteria such as landscape, NDVI, and cluster analysis. In addition, it was investigated if the aspect or slope of the terrain influenced to the classification of tombs. As a result of this research, authors find that there is similarity between the classification tv NDVI and the classification through cluster analysis. And aspect or slope didn't have much influence on the classification of tombs.